Call it the flight from perfection. The gap-toothed smile flashed by some of today's top models is leading to a Stateside boom in quirky dental treatment in place of the perfect, straight white smiles for which young Americans have historically endured years of treatment.

The popularity of models such as Jess Hart, Lara Stone and Georgia Jagger has increased demand for cosmetic orthodontic procedures. Some models are having brackets inserted between their front teeth to widen the gap and improve their careers and American dentists report that veneers with slight staining, grooves and overlaps are growing in popularity.

Last week the New York Times reported that demand is growing for customised imperfect veneers despite the cost of up to $2,500. Standard veneers cost around $700. "The white standard got too white," one Manhattan dentist told the paper. "The perfection standard got too perfect."

The gap-toothed pout has been one of fashion's most sought-after accessories for the past two seasons, kicked off by Australian model Jessica Hart's appearance in the 2009 Sports Illustrated swimsuit issue and culminating with supermodel, and the current face of Calvin Klein, Lara Stone becoming the poster girl for the diastema.

British consumers may soon be imitating their American counterparts. Mick Jagger's daughter Georgia – gap to the fore – is on the cover of the latest edition of British Vogue and appears in ad campaigns for Versace and Hudson jeans.

Unusual beauty has become a major trend in the fashion industry, while recent catwalk shows and ad campaigns have also focused on unconventional looks. Redheads are enjoying a renaissance in fashion. Top British brand Mulberry's last show featured models all clad in copper wigs, inspired, says the company's creative director, Emma Hill, by Finnish model Julia Johansen.

The high-street brand Jigsaw featured two flame-haired girls – Jessie Good and Poppy Delevigne – in its autumn ad campaign. Good is the daughter of Jigsaw's co-founder Belle Robinson and has just been signed to top model agency Storm. "She's the only redhead in our family – poor old Jessie hated being a redhead as a child," says Robinson.

"She didn't look like anyone else in her family and she didn't look like her friends. But she has the most incredible hair, and slowly but surely she began to love it herself. Redheads are being embraced in a major way because nine times out of 10 it's their natural hair colouring, so there's a purity to them."

The fascination with natural looks has been evident in recent fashion shows. At the autumn/winter 2010 Prada show, girls wore unglamorous, librarian-style glasses. Strong, natural-looking eyebrows were seen on Chloe's catwalk. The models at Marc by Marc Jacobs all had morning-after make-up that looked rough and lived in, and messy hair was seen at Narciso Rodriguez's New York show. "There is something in the air now which is seeing people move away from the stylised looks we are used to seeing on the red carpet and towards the more natural," said hair stylist Guido Palau after Jacobs's show.

Liz Hambleton, beauty director of Grazia, agreed: "I think we're maxed out on perfection and looking for something a little more real at the moment. A gappy tooth, tons of freckles, huge geek chic glasses all give someone so much more personality than a glossy blow-out and a fake tan. I'm more interested in looking at the Lara Stones and Karen Elsons of this world than Cheryl Cole."

"I think that odd beauties really show off the current clothes well," said Harriet Quick, fashion features director at Vogue. "At the moment fashion is rethinking classics and is focused on making real clothes. These girls make you look twice and see fashion in a surprising new light."

"It goes back to that Parisian beauty mantra of not looking done but actually being extremely done," said Hambleton. "It's about spending time and, yes, money cultivating great skin and hair in order to avoid having to style it and wear make-up. A great skincare regime makes the difference between wearing foundation or not."